Filtering OData feed

Hello,

I'm attempting to filter the data I'm receiving via my OData feed with MS Project Online.  I'm pulling multiple tables into the PowerBI dataset and the filter will be on just one of the tables.  Specifically, ProjectName from the Projects table.

My query is as follows:

https://company.sharepoint.com/sites/PWASite/_api/Projectdata/projects?$filter=ProjectName eq 'Test Project'

The error I'm receiving when I apply the query changes is for the Assignments table and it reads as follows:

OData: Rsource not found for the segment 'projects'.

Is there something wrong with my filter syntax?  I'm also wondering if I need to specify the URL in parts as I'm sampling multiple tables and what those parts might be.  I couldn't find much about URL parts in the OData.org URL conventions.